Conventionally, images in recording devices such as printers and copiers were generally formed by Carlson's electrophotography.
Electrophotography of the Carlson's system has been widely employed for forming images in photocopying and printing. Electrophotography uses a drum having a photosensitive surface which passes a charging section where the photosensitive surface is uniformly charged, an exposure section where the photosensitive surface is exposed to a light image or a pattern of light which corresponds to the original (source document) or the print data to form an electrostatic latent image consisting of charged areas and discharged areas, a developing section where toner is attracted to the charged areas of the latent image so that a toner image is created, a transfer section where the toner image is transferred to a recording paper which is brought into contact with the photosensitive drum, and a cleaning section which removes any residual toner on the photosensitive surface. The toner image that has been transferred to the recording paper is fixed by application of heat, for example, and the recording paper is then discharged from the apparatus.
A problem associated with the prior system is that because various devices must be disposed on the periphery of the photosensitive drum, the drum must have a sufficient diameter, and the cost of the drum is high, and the overall apparatus is bulky.
Another problem is that there is a considerable amount of toner remaining on the photosensitive drum after the transfer of the toner image. This residual toner must be removed by a cleaning device, and must be collected and then disposed. When the collected toner is disposed, the toner may be scattered in and out of the apparatus, and the operator's clothing or body may be soiled.
To overcome these drawbacks, an image forming system has been proposed in which a toner image bearing belt is passed around a photosensitive drum and through a transfer section, a developing device is provided facing the toner image bearing belt passing over the photosensitive drum on which an electrostatic latent image has been formed, for causing toner to be attracted toward the photosensitive drum, and thereby forming a toner image on the toner image bearing belt which is passes around the photosensitive drum, and the toner image on the toner image bearing belt is transferred to a recording paper that is brought into contact with the toner image bearing belt at the transfer section.
In the system described above, when the toner image on toner image bearing belt was transferred to and fixed on the recording paper, some disturbances were found to occur in the image reproduced on the recording paper. Upon examination, it has been found that the toner on the toner image bearing belt scattered when the toner image bearing belt separated from the photosensitive drum.